Case wall pressures in a multistage axial compressor with tip clearance variation

Large cyclical pressure excursions from stator-averaged values are observed on the suction side of a rotor blade at the case wall in a multistage compressor as the rotor moves relative to the stator. The pressure changes correlate well with stator relative position, occur in the passage away from the blade, and are only slightly modified by tip clearance changes. Close to the entry and exit of the tip gap, however, the pressures remain stable. The pressures near the gap are only slightly affected by stator proximity and primarily vary with tip gap height.